Hook-in type metal shelving is well known. Such shelving employs vertical support posts having a plurality of spaced slots. Pairs of posts are interconnected to form rectangular end frames by locking the hooked ends of horizontal post connectors into the post slots. At least two horizontal post connectors are used; one between the upper ends of the posts and another between the lower ends of the posts. Additional horizontal post connectors may be locked between the posts at points intermediate their upper and lower ends to further strengthen and stabilize the end frame. Pairs of end frames are then interconnected to form a rectangular-based shelving unit by connecting the hooked ends of horizontal frame connectors between the slots of opposing end frame posts. The horizontal frame connectors also serve to support the shelves, although additional shelf support brackets may be connected between the posts.
It is known to provide the hooked ends of the post connectors with locking tabs as exemplified by U.S. Pat. No. 4,063,835 to Husband et al., issued Dec. 20, 1977. As disclosed by Husband et al., once a hooked end has been fitted into a corresponding post slot, a locking tab on that hooked end is bent against the post to prevent accidental withdrawal of that hooked end from the post. If it is desired to dismantle the shelving unit, rearrange the shelves, etc. then a levering implement such as a screwdriver can be wedged between the post and the locking tab and used to pry the locking tab away from the post, back into its original unlocked position.
According to U.S. Pat. No. 4,157,228 to Hammerschlag, issued June 5, 1979; and, U.S. Pat No. 4,341,486 to Hammerschlag, issued July 27, 1982 (see also corresponding Canadian Patent Nos. 1,065,280 and 1,065,281 issued 30 Oct., 1979) it can be difficult to unlock the Husband et al. locking tabs, once they have been locked against the posts. Hammerschlag's locking tabs have upper surfaces which are slanted backwards and downwards when unlocked. When Hammerschlag's locking tabs are locked by bending them against the vertical posts, the upper surfaces of the locking tabs are either perpendicular to the centre line of the post; or, retain some backward, downward slant relative to the centre line of the post. A secondary portion of Hammerschlag's locking tab remains spaced from the post when the locking tab is locked, leaving room for insertion of a screwdriver between the secondary portion and the post. The screwdriver can then be used to pry the locking tab back into its original unlocked position in order to facilitate removal of the post connector's hooked end from the post.
The present invention provides an improved locking tab structure which may, if desired, be unlocked in either of two ways.